Comparative Analysis of Phytoaccumulation Abilities of Several Crop Plants under Combined Heavy Metal Contamination

The study evaluated the phytoaccumulation potential of eleven crop species under single and combined Pb²⁺, Zn²⁺, and Fe³⁺ contamination at concentrations typical of military equipment combustion sites in Ukraine. Combined metal stress caused stronger phytotoxic effects than single-metal treatments. Brassica napus demonstrated the highest tolerance and accumulation capacity, maintaining high germination rates and achieving a translocation factor (TF) for Zn²⁺ of up to 17.1. Sorghum sudanense (light-seeded form) also showed strong potential, particularly for Pb²⁺ (TF up to 10.3). In contrast, wheat, maize, and amaranth exhibited poor germination under combined contamination. White clover and alfalfa displayed moderate phytostabilization ability (TF < 1 for Pb²⁺). The optimized SpHMA2 gene sequence was prepared for future transgenic enhancement of metal uptake in B. napus.